Download Math109Quiz2Fall2011

North Seattle Community College
Fall Quarter 2011
ELEMENTARY STATISTICS
2618 MATH 109 - Section 05
Chapter 3 and 4 - Quiz 2
STUDENT NAME: __________________________
24th October 2011
QUIZ SCORE: ______________________________
Problem 1: 5 points
Indentify the sample space and the number of elements in the sample space of
the probability experiment and determine the number of outcomes in the event.
Draw a tree diagram.
Experiment: Guessing the gender of the three children in a family
Event: The family has two boys.
Problem 2: (7 points)
A deck of cards has 52 cards with 13 hearts. A gambling game consists of a player
drawing three cards without replacement. The required bet is $1000 i.e. you
need $10 to buy into the game. The winnings depend on the number of hearts
drawn out of the three cards. If you get no hearts you win $0, for 1 heart you
receive $10, for 2 hearts you can win 20 and for all hearts you can win 500.
1. What is the probability distribution for number of hearts drawn?
2. What would be the average gain?
3. What is the variance and standard deviation for the gain?
Problem 3: (5 points)
Suppose that 60% of all people would like to see gun control laws strengthened.
In sampling 10 people randomly (with replacement), let x represent the number
of people who would like to see gun control laws strengthened.
1. What is the probability that at least 3 of the 10 people surveyed would like gun
control strengthened?
2. What is the mean for the number of people who would like gun control
strengthened?
3. What is the variance and standard deviation for the number of people who
would like gun control strengthened?
Problem 4: (8 points)
Consider the sample space below. Each smiley face is an outcome in the sample
space. Outcomes in the larger circle count as Event A. Outcomes in the smaller
circle count as event B.
A
B
1. What is the P(A)? What is the P(B)?
2. What is the P(A | B)?
3. What is the P(A and B)?
4. Are A and B mutually exclusive events? Explain using probabilities.
5. Are A and B independent events? Explain using probabilities.